1. Field of the Invention
The present invention relates to an interlace noise filter which enables the obtaining of a high resolution still image from an interlace motion image.
2. Prior Art
Scanning system for television is generally called an interlace system. In Japan, for example, 525 scan lines are first scanned every other scan line, thereby forming one original image in the odd number field, then respective scan lines between the first scanned scan lines are scanned, thereby forming the other original image in the even number fields. In other words, an entire original image is transmitted through twice scanning. The interlace system is advantageous in that it can present less flickers and more smooth images. If the number of images transmitted for one second (simply called the number of transmission images) is relatively small, a motion picture thus obtained becomes unnatural, and thus, the number has been set to 30 images per one second. Accordingly, the scanning of one image (frame scanning) takes {fraction (1/30)} sec., and thus one scanning operation according to interlace system is performed in {fraction (1/60)} sec.
According to interlace system, whilst a motion picture is not visually affected in particular, print-out or motion-stop of video images or the like on a television screen is adversely affected such that two images displaced by {fraction (1/30)} sec. are displayed or printed out with the former image being shifted relative to the latter, so that an entire image thus obtained becomes so hard to make out. This is particularly true of a picture of a relatively quick motion. On the other hand, if print-out or motion-stop is carried out, using an image through the first image scanning only (i.e., an original image either in the odd number field or in the even number field) in order to prevent the images from being shifted, there are problems that the resulting image would become too rough to see, and some colors would be dropped out due to the output of gradation in the odd or even number field only.
To eliminate the above-mentioned problems, it is, therefore, an object of the present invention to provide an interlace noise filter which enables a high resolution still image to be obtained from a motion picture according to interlace system.
To attain the above objects, there is proposed an interlace noise filter which comprises: a sampling means for sampling an original image in an even number field out of an interlace original image; a transforming means for Haar wavelets transformation of sampled image data; a reconstituting means for constructing new image data through an inverse transformation of the Haar wavelets transformed data; and an output means for outputting thus reconstituted new image data together with an original image in an odd number field.